A set of organic molecules including carbohydrates, organic amine compounds, and lipids is common to all known life.
The similarity lies in all organic molecules having the same type of structure in every organism.
C – C – C – C chains of carbon with the potential for huge long side chains etc.
Organic molecules are essential to life.
Just a few examples of organic molecules:
All organtic things are made up of carbon.
Because they exist in everything